Method and apparatus for transmission of control and data in vehicle to vehicle communication

ABSTRACT

A user equipment (UE) and base station (BS) in a wireless communication network. The UE includes a receiver configured to receive at least one semi-persistent scheduling (SPS) configuration among a plurality of SPS configurations from a BS. Each of the SPS configurations configures the UE with a different periodicity of a sidelink transmission to be transmitted to another UE. The UE also includes a transmitter configured to transmit the sidelink transmission in the different periodicity according to the at least one of the plurality of SPS configurations. The BS includes a controller configured to select at least one SPS configuration among a plurality of SPS configurations for a UE. Each of the SPS configurations configures the UE with a different periodicity of a sidelink transmission to be transmitted to another UE. The BS also includes a transmitter configured to transmit the selected at least one SPS configuration to the UE.

CROSS-REFERENCE TO RELATED APPLICATION AND CLAIMS OF PRIORITY

This application claims priority under 35 U.S.C. § 119(e) to: U.S.Provisional Patent Application No. 62/316,182 filed on Mar. 31, 2016;U.S. Provisional Patent Application No. 62/320,128 filed on Apr. 8,2016; U.S. Provisional Patent Application No. 62/333,512 filed on May 9,2016; U.S. Provisional Patent Application No. 62/334,179 filed on May10, 2016; and U.S. Provisional Patent Application No. 62/335,368 filedon May 12, 2016. The above-identified provisional patent applicationsare hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates generally to wireless communicationsystems and, more specifically, to communication network protocols,including vehicle-to-device, vehicle-to-vehicle, and vehicle-to-networkcommunication resource allocation and synchronization methods.

BACKGROUND

Traditionally, cellular communication networks have been designed toestablish wireless communication links between mobile devices and fixedcommunication infrastructure components (such as base stations or accesspoints) that serve users in a wide or local geographic range. However, awireless network can also be implemented to utilize onlydevice-to-device (D2D) communication links without a need for fixedinfrastructure components. This type of network is typically referred toas an ad-hoc network. A hybrid communication network can support devicesthat connect both to fixed infrastructure components and to otherD2D-enabled devices. While end user devices such as smartphones may beenvisioned for D2D communication networks, a vehicular communicationnetwork, such as vehicle to everything (V2X) may be supported by acommunication protocol where vehicles exchange control and datainformation between other vehicles (vehicle to vehicle (V2V)) or otherinfrastructure (vehicle to infrastructure (V2I)) and end-user devices(vehicle to pedestrian (V2P)). Multiple types of communication links maybe supported by nodes providing V2X communication in a network, andutilizing the same or different protocols and systems.

SUMMARY

Various embodiments of the present disclosure provide methods andapparatuses for the transmission of control and data in vehicle tovehicle communication.

In a first embodiment, a user equipment (UE) in a wireless communicationnetwork includes a receiver configured to receive at least onesemi-persistent scheduling (SPS) configuration among a plurality of SPSconfigurations from a base station. Each of the plurality of SPSconfigurations configures the UE with a different periodicity of asidelink transmission to be transmitted to another UE. The UE alsoincludes a transmitter configured to transmit the sidelink transmissionin the different periodicity according to the at least one received SPSconfiguration.

In a second embodiment, a BS in a wireless communication networkincludes a controller configured to select at least one SPSconfiguration among a plurality of SPS configurations for a UE. Each ofthe plurality of SPS configurations configures the UE with a differentperiodicity of a sidelink transmission to be transmitted to another UE.The BS also includes a transmitter configured to transmit the selectedat least one SPS configuration to the UE.

In a third embodiment, a method for operating a UE in a wirelesscommunication network comprises receiving at least one semi-persistentscheduling (SPS) configuration among a plurality of SPS configurationsfrom a base station. Each of the plurality of SPS configurationsconfigures the UE with a different periodicity of a sidelinktransmission to be transmitted to another UE. The method furtherincludes transmitting the sidelink transmission with a periodicityaccording to the at least one received SPS configuration.

Other technical features may be readily apparent to one skilled in theart from the following figures, descriptions, and claims.

Before undertaking the DETAILED DESCRIPTION below, it can beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document. The term “couple” and its derivativesrefer to any direct or indirect communication between two or moreelements, whether or not those elements are in physical contact with oneanother. The terms “transmit,” “receive,” and “communicate,” as well asderivatives thereof, encompass both direct and indirect communication.The terms “include” and “comprise,” as well as derivatives thereof, meaninclusion without limitation. The term “or” is inclusive, meaningand/or. The phrase “associated with,” as well as derivatives thereof,means to include, be included within, interconnect with, contain, becontained within, connect to or with, couple to or with, be communicablewith, cooperate with, interleave, juxtapose, be proximate to, be boundto or with, have, have a property of, have a relationship to or with, orthe like. The term “controller” means any device, system or part thereofthat controls at least one operation. Such a controller can beimplemented in hardware or a combination of hardware and software and/orfirmware. The functionality associated with any particular controllercan be centralized or distributed, whether locally or remotely. Thephrase “at least one of,” when used with a list of items, means thatdifferent combinations of one or more of the listed items can be used,and only one item in the list can be needed. For example, “at least oneof: A, B, and C” includes any of the following combinations: A, B, C, Aand B, A and C, B and C, and A and B and C.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for other certain words and phrases are provided throughoutthis patent document. Those of ordinary skill in the art shouldunderstand that in many if not most instances, such definitions apply toprior as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an example wireless network according to someembodiments of the present disclosure;

FIGS. 2A and 2B illustrate example wireless transmit and receive pathsaccording to some embodiments of the present disclosure;

FIG. 3A illustrates an example user equipment according to someembodiments of the present disclosure;

FIG. 3B illustrates an example enhanced NodeB (eNB) according to someembodiments of the present disclosure;

FIG. 4 illustrates an example use case of a vehicle-centriccommunication network according to illustrative embodiments of thepresent disclosure;

FIG. 5 illustrates an example sidelink (SL) interface according toillustrative embodiments of the present disclosure;

FIG. 6 illustrates an example resource pool for Physical SidelinkControl Channel (PSCCH) according to illustrative embodiments of thepresent disclosure;

FIG. 7 illustrates an example subframe resource allocation according toillustrative embodiments of the present disclosure;

FIG. 8 shows an example of Cooperative Awareness Messages (CAM) messageperiodicity as a function of UE speed according to the embodiments ofthis disclosure;

FIG. 9 illustrates an example of the semi-persistent CAM messagestransmitted by the vehicle UE to the eNodeB (eNB) or to other UEs,according to the embodiments of this disclosure;

FIG. 10 shows an example of a shared resource allocation for uplink (UL)semi-persistent transmissions according to the embodiments of thisdisclosure;

FIG. 11 shows an example embodiment of this disclosure, where theresources are allocated in the shared set according to dynamicperiodicity;

FIG. 12 shows an example design of Semi-persistent scheduling (SPS)configuration types according to the embodiments of this disclosure;

FIG. 13 shows the SPS operation for Mode 1 operation, where the UE has asingle SPS process at a given time, but can switch between multiple SPSprocesses, according to the embodiments of this disclosure;

FIG. 14 shows the SPS operation for Mode 1 operation where the UE hassimultaneous SPS processes running in parallel, according to theembodiments of this disclosure;

FIG. 15 shows the partitioning of the messages by the UE for SPS andnon-SPS transmissions, based on an embodiment of this disclosure;

FIG. 16 shows the fragmentation of the V2X messages into multipletransport blocks for SPS and transmission on different subframes,according to the embodiments of this disclosure;

FIG. 17 shows an example of semi-persistent transmissions from multipleUEs in the shared resource pool for SL according to one embodiment ofthis disclosure;

FIG. 18 shows an embodiment of the disclosure where the UE stops the SPStransmissions and changes to regular transmissions until the periodicityis stabilized;

FIG. 19 shows an example procedure for transmitting messages usingperiodic and regular resource allocation, according to embodiments ofthe present disclosure;

FIG. 20 shows another example procedure for transmitting messages usingperiodic and regular resource allocation, according to embodiments ofthe present disclosure;

FIG. 21 illustrates an example of comparing the different SPS allocationschemes according to embodiments of the present disclosure;

FIG. 22 shows another example of comparing the different SPS allocationschemes according to embodiments of the present disclosure; and

FIG. 23 shows yet another example of comparing the different SPSallocation schemes according to embodiments of the present disclosure;

FIG. 24 illustrates an example resource pool structure using frequencydivision multiplexing of SA and data according to illustrativeembodiments of the present disclosure;

FIG. 25 illustrates example resource pool structures using frequencydivision multiplexing of SA and data on separate physical channelsaccording to illustrative embodiments of the present disclosure;

FIG. 26A to 26C illustrate the resource allocations for PhysicalSidelink Shared Channel (PSSCH) transmissions according to embodimentsof the present disclosure;

FIG. 27 illustrates an example periodic preamble that can be transmittedby V2V in order to facilitate detection by Dedicate Short RangeCommunication (DSRC) receivers according to embodiments of the presentdisclosure;

FIG. 28 shows an option using wideband transmissions to enable carriersense/clear channel assessment at DSRC receivers according toembodiments of the present disclosure; and

FIG. 29 shows how a V2V receiver can distinguish between a DSRCtransmission and a LTE V2V transmission, according to the embodiments ofthis disclosure.

DETAILED DESCRIPTION

FIGS. 1 through 29, discussed below, and the various embodiments used todescribe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged wireless communication system.

The following documents and standards descriptions are herebyincorporated by reference into the present disclosure as if fully setforth herein:

3rd generation partnership project (3GPP) TS 36.211 v13.0, “E-UTRA,Physical channels and modulation” (“REF 1”); 3GPP TS 36.212 v13.0,“E-UTRA, Multiplexing and Channel coding” (“REF 2”); 3GPP TS 36.213v13.0, “E-UTRA, Physical Layer Procedures” (“REF 3”); 3GPP TS 36.321v13.0, “E-UTRA, Medium Access Control (MAC) protocol specification”(“REF 4”); 3GPP TS 36.331 v13.0, “E-UTRA, Radio Resource Control (RRC)Protocol Specification” (“REF 5”); 3GPP TS 23.303 v13.2.0,“Proximity-based services (ProSe); Stage 2” (“REF 6”); 3GPP TS 22.885v14.0.0, “Study on LTE support for V2X services” (“REF 7”); andR1-161527, “Observations on CAM message periodicity and payload,”Ericsson (“REF 8”).

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a ‘Beyond 4G Network’ or a‘Post LTE System’.

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higherdata rates. To decrease propagation loss of the radio waves and increasethe transmission distance, the beamforming, massive multiple-inputmultiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna,an analog beam forming, large scale antenna techniques are discussed in5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud RadioAccess Networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul, moving network, cooperativecommunication, Coordinated Multi-Points (CoMP), reception-endinterference cancellation and the like.

In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and slidingwindow superposition coding (SWSC) as an advanced coding modulation(ACM), and filter bank multi carrier (FBMC), non-orthogonal multipleaccess (NOMA), and sparse code multiple access (SCMA) as an advancedaccess technology have been developed.

FIG. 1 illustrates an example wireless network 100 according to someembodiments of the present disclosure. The embodiment of the wirelessnetwork 100 shown in FIG. 1 is for illustration only. Other embodimentsof the wireless network 100 could be used without departing from thescope of this disclosure.

The wireless network 100 includes an eNodeB (eNB) 101, an eNB 102, andan eNB 103. The eNB 101 communicates with the eNB 102 and the eNB 103.The eNB 101 also communicates with at least one Internet Protocol (IP)network 130, such as the Internet, a proprietary IP network, or otherdata network.

Depending on the network type, other well-known terms may be usedinstead of “eNodeB” or “eNB,” such as “base station” or “access point.”For the sake of convenience, the terms “eNodeB” and “eNB” are used inthis patent document to refer to network infrastructure components thatprovide wireless access to remote terminals. Also, depending on thenetwork type, other well-known terms may be used instead of “userequipment” or “UE,” such as “mobile station,” “subscriber station,”“remote terminal,” “wireless terminal,” or “user device.” For the sakeof convenience, the terms “user equipment” and “UE” are used in thispatent document to refer to remote wireless equipment that wirelesslyaccesses an eNB, whether the UE is a mobile device (such as a mobiletelephone or smartphone) or is normally considered a stationary device(such as a desktop computer or vending machine).

The eNB 102 provides wireless broadband access to the network 130 for afirst plurality of user equipments (UEs) within a coverage area 120 ofthe eNB 102. The first plurality of UEs includes a UE 111, which may belocated in a small business (SB); a UE 112, which may be located in anenterprise (E); a UE 113, which may be located in a WiFi hotspot (HS); aUE 114, which may be located in a first residence (R); a UE 115, whichmay be located in a second residence (R); and a UE 116, which may be amobile device (M) like a cell phone, a wireless laptop, a wireless PDA,or the like. The eNB 103 provides wireless broadband access to thenetwork 130 for a second plurality of UEs within a coverage area 125 ofthe eNB 103. The second plurality of UEs includes the UE 115 and the UE116. In some embodiments, one or more of the eNBs 101-103 maycommunicate with each other and with the UEs 111-116 using 5G, long-termevolution (LTE), LTE-A, WiMAX, or other advanced wireless communicationtechniques.

Dotted lines show the approximate extents of the coverage areas 120 and125, which are shown as approximately circular for the purposes ofillustration and explanation only. It should be clearly understood thatthe coverage areas associated with eNBs, such as the coverage areas 120and 125, may have other shapes, including irregular shapes, dependingupon the configuration of the eNBs and variations in the radioenvironment associated with natural and man-made obstructions.

As described in more detail below, one or more of BS 101, BS 102 and BS103 include 2D antenna arrays as described in embodiments of the presentdisclosure. In some embodiments, one or more of BS 101, BS 102 and BS103 support the transmission of control and data in vehicle to vehiclecommunication.

Although FIG. 1 illustrates one example of a wireless network 100,various changes may be made to FIG. 1. For example, the wireless network100 could include any number of eNBs and any number of UEs in anysuitable arrangement. Also, the eNB 101 could communicate directly withany number of UEs and provide those UEs with wireless broadband accessto the network 130. Similarly, each eNB 102-103 could communicatedirectly with the network 130 and provide UEs with direct wirelessbroadband access to the network 130. Further, the eNB 101, 102, and/or103 could provide access to other or additional external networks, suchas external telephone networks or other types of data networks.

FIGS. 2A and 2B illustrate example wireless transmit and receive pathsaccording to some embodiments of the present disclosure. In thefollowing description, a transmit path 200 may be described as beingimplemented in an eNB (such as eNB 102), while a receive path 250 may bedescribed as being implemented in a UE (such as UE 116). However, itwill be understood that the receive path 250 could be implemented in aneNB and that the transmit path 200 could be implemented in a UE. In someembodiments, the receive path 250 is configured to support thetransmission of control and data in vehicle to vehicle communication.

The transmit path 200 includes a channel coding and modulation block205, a serial-to-parallel (S-to-P) block 210, a size N Inverse FastFourier Transform (IFFT) block 215, a parallel-to-serial (P-to-S) block220, an add cyclic prefix block 225, and an up-converter (UC) 230. Thereceive path 250 includes a down-converter (DC) 255, a remove cyclicprefix block 260, a serial-to-parallel (S-to-P) block 265, a size N FastFourier Transform (FFT) block 270, a parallel-to-serial (P-to-S) block275, and a channel decoding and demodulation block 280.

In the transmit path 200, the channel coding and modulation block 205receives a set of information bits, applies coding (such as alow-density parity check (LDPC) coding), and modulates the input bits(such as with Quadrature Phase Shift Keying (QPSK) or QuadratureAmplitude Modulation (QAM)) to generate a sequence of frequency-domainmodulation symbols. The serial-to-parallel block 210 converts (such asde-multiplexes) the serial modulated symbols to parallel data in orderto generate N parallel symbol streams, where N is the IFFT/FFT size usedin the eNB 102 and the UE 116. The size N IFFT block 215 performs anIFFT operation on the N parallel symbol streams to generate time-domainoutput signals. The parallel-to-serial block 220 converts (such asmultiplexes) the parallel time-domain output symbols from the size NIFFT block 215 in order to generate a serial time-domain signal. The addcyclic prefix block 225 inserts a cyclic prefix to the time-domainsignal. The up-converter 230 modulates (such as up-converts) the outputof the add cyclic prefix block 225 to an RF frequency for transmissionvia a wireless channel. The signal may also be filtered at basebandbefore conversion to the RF frequency.

A transmitted RF signal from the eNB 102 arrives at the UE 116 afterpassing through the wireless channel, and reverse operations to those atthe eNB 102 are performed at the UE 116. The down-converter 255down-converts the received signal to a baseband frequency, and theremove cyclic prefix block 260 removes the cyclic prefix to generate aserial time-domain baseband signal. The serial-to-parallel block 265converts the time-domain baseband signal to parallel time domainsignals. The size N FFT block 270 performs an FFT algorithm to generateN parallel frequency-domain signals. The parallel-to-serial block 275converts the parallel frequency-domain signals to a sequence ofmodulated data symbols. The channel decoding and demodulation block 280demodulates and decodes the modulated symbols to recover the originalinput data stream.

Each of the eNBs 101-103 may implement a transmit path 200 that isanalogous to transmitting in the downlink to UEs 111-116 and mayimplement a receive path 250 that is analogous to receiving in theuplink from UEs 111-116. Similarly, each of UEs 111-116 may implement atransmit path 200 for transmitting in the uplink to eNBs 101-103 and mayimplement a receive path 250 for receiving in the downlink from eNBs101-103.

Each of the components in FIGS. 2A and 2B can be implemented using onlyhardware or using a combination of hardware and software/firmware. As aparticular example, at least some of the components in FIGS. 2A and 2Bmay be implemented in software, while other components may beimplemented by configurable hardware or a mixture of software andconfigurable hardware. For instance, the FFT block 270 and the IFFTblock 215 may be implemented as configurable software algorithms, wherethe value of size N may be modified according to the implementation.

Furthermore, although described as using FFT and IFFT, this is by way ofillustration only and should not be construed to limit the scope of thisdisclosure. Other types of transforms, such as Discrete FourierTransform (DFT) and Inverse Discrete Fourier Transform (IDFT) functions,could be used. It will be appreciated that the value of the variable Nmay be any integer number (such as 1, 2, 3, 4, or the like) for DFT andIDFT functions, while the value of the variable N may be any integernumber that is a power of two (such as 1, 2, 4, 8, 16, or the like) forFFT and IFFT functions.

Although FIGS. 2A and 2B illustrate examples of wireless transmit andreceive paths, various changes may be made to FIGS. 2A and 2B. Forexample, various components in FIGS. 2A and 2B could be combined,further subdivided, or omitted and additional components could be addedaccording to particular needs. Also, FIGS. 2A and 2B are meant toillustrate examples of the types of transmit and receive paths thatcould be used in a wireless network. Any other suitable architecturescould be used to support wireless communications in a wireless network.

FIG. 3A illustrates an example UE 116 according to some embodiments ofthe present disclosure. The embodiment of the UE 116 illustrated in FIG.3A is for illustration only, and the UEs 111-115 of FIG. 1 could havethe same or similar configuration. However, UEs come in a wide varietyof configurations, and FIG. 3A does not limit the scope of thisdisclosure to any particular implementation of a UE.

The UE 116 includes an antenna 305, a radio frequency (RF) transceiver310, transmit (TX) processing circuitry 315, a microphone 320, andreceive (RX) processing circuitry 325. The UE 116 also includes aspeaker 330, a main processor 340, an input/output (I/O) interface (IF)345, a keypad 350, a display 355, and a memory 360. The memory 360includes a basic operating system (OS) program 361 and one or moreapplications 362.

The RF transceiver 310 receives, from the antenna 305, an incoming RFsignal transmitted by an eNB of the network 100. The RF transceiver 310down-converts the incoming RF signal to generate an intermediatefrequency (IF) or baseband signal. The IF or baseband signal is sent tothe RX processing circuitry 325, which generates a processed basebandsignal by filtering, decoding, and/or digitizing the baseband or IFsignal. The RX processing circuitry 325 transmits the processed basebandsignal to the speaker 330 (such as for voice data) or to the mainprocessor 340 for further processing (such as for web browsing data).

The TX processing circuitry 315 receives analog or digital voice datafrom the microphone 320 or other outgoing baseband data (such as webdata, e-mail, or interactive video game data) from the main processor340. The TX processing circuitry 315 encodes, multiplexes, and/ordigitizes the outgoing baseband data to generate a processed baseband orIF signal. The RF transceiver 310 receives the outgoing processedbaseband or IF signal from the TX processing circuitry 315 andup-converts the baseband or IF signal to an RF signal that istransmitted via the antenna 305.

The main processor 340 can include one or more processors or otherprocessing devices and execute the basic OS program 361 stored in thememory 360 in order to control the overall operation of the UE 116. Forexample, the main processor 340 could control the reception of forwardchannel signals and the transmission of reverse channel signals by theRF transceiver 310, the RX processing circuitry 325, and the TXprocessing circuitry 315 in accordance with well-known principles. Insome embodiments, the main processor 340 includes at least onemicroprocessor or microcontroller.

The main processor 340 is also capable of executing other processes andprograms resident in the memory 360, such as operations for channelquality measurement and reporting for systems having 2D antenna arraysas described in embodiments of the present disclosure as described inembodiments of the present disclosure. The main processor 340 can movedata into or out of the memory 360 as required by an executing process.In some embodiments, the main processor 340 is configured to execute theapplications 362 based on the OS program 361 or in response to signalsreceived from eNBs or an operator. The main processor 340 is alsocoupled to the I/O interface 345, which provides the UE 116 with theability to connect to other devices such as laptop computers andhandheld computers. The I/O interface 345 is the communication pathbetween these accessories and the main controller 340.

The main processor 340 is also coupled to the keypad 350 and the displayunit 355. The operator of the UE 116 can use the keypad 350 to enterdata into the UE 116. The display 355 may be a liquid crystal display orother display capable of rendering text and/or at least limitedgraphics, such as from web sites.

The memory 360 is coupled to the main processor 340. Part of the memory360 could include a random access memory (RAM), and another part of thememory 360 could include a Flash memory or other read-only memory (ROM).

Although FIG. 3A illustrates one example of UE 116, various changes maybe made to FIG. 3A. For example, various components in FIG. 3A could becombined, further subdivided, or omitted and additional components couldbe added according to particular needs. As a particular example, themain processor 340 could be divided into multiple processors, such asone or more central processing units (CPUs) and one or more graphicsprocessing units (GPUs). Also, while FIG. 3A illustrates the UE 116configured as a mobile telephone or smartphone, UEs could be configuredto operate as other types of mobile or stationary devices.

FIG. 3B illustrates an example eNB 102 according to some embodiments ofthe present disclosure. The embodiment of the eNB 102 shown in FIG. 3Bis for illustration only, and other eNBs of FIG. 1 could have the sameor similar configuration. However, eNBs come in a wide variety ofconfigurations, and FIG. 3B does not limit the scope of this disclosureto any particular implementation of an eNB. It is noted that eNB 101 andeNB 103 can include the same or similar structure as eNB 102.

As shown in FIG. 3B, the eNB 102 includes multiple antennas 370 a-370 n,multiple RF transceivers 372 a-372 n, transmit (TX) processing circuitry374, and receive (RX) processing circuitry 376. In certain embodiments,one or more of the multiple antennas 370 a-370 n include 2D antennaarrays. The eNB 102 also includes a controller/processor 378, a memory380, and a backhaul or network interface 382.

The RF transceivers 372 a-372 n receive, from the antennas 370 a-370 n,incoming RF signals, such as signals transmitted by UEs or other eNBs.The RF transceivers 372 a-372 n down-convert the incoming RF signals togenerate IF or baseband signals. The IF or baseband signals are sent tothe RX processing circuitry 376, which generates processed basebandsignals by filtering, decoding, and/or digitizing the baseband or IFsignals. The RX processing circuitry 376 transmits the processedbaseband signals to the controller/processor 378 for further processing.

The TX processing circuitry 374 receives analog or digital data (such asvoice data, web data, e-mail, or interactive video game data) from thecontroller/processor 378. The TX processing circuitry 374 encodes,multiplexes, and/or digitizes the outgoing baseband data to generateprocessed baseband or IF signals. The RF transceivers 372 a-372 nreceive the outgoing processed baseband or IF signals from the TXprocessing circuitry 374 and up-converts the baseband or IF signals toRF signals that are transmitted via the antennas 370 a-370 n.

The controller/processor 378 can include one or more processors or otherprocessing devices that control the overall operation of the eNB 102.For example, the controller/processor 378 could control the reception offorward channel signals and the transmission of reverse channel signalsby the RF transceivers 372 a-372 n, the RX processing circuitry 376, andthe TX processing circuitry 374 in accordance with well-knownprinciples. The controller/processor 378 could support additionalfunctions as well, such as more advanced wireless communicationfunctions. For instance, the controller/processor 378 can perform theblind interference sensing (BIS) process, such as performed by a BISalgorithm, and decodes the received signal subtracted by the interferingsignals. Any of a wide variety of other functions could be supported inthe eNB 102 by the controller/processor 378. In some embodiments, thecontroller/processor 378 includes at least one microprocessor ormicrocontroller.

The controller/processor 378 is also capable of executing programs andother processes resident in the memory 380, such as a basic OS. Thecontroller/processor 378 is also capable of supporting the transmissionof control and data in vehicle to vehicle communication as described inembodiments of the present disclosure. In some embodiments, thecontroller/processor 378 supports communications between entities, suchas web Real-Time Communication (RTC). The controller/processor 378 canmove data into or out of the memory 380 as required by an executingprocess.

The controller/processor 378 is also coupled to the backhaul or networkinterface 382. The backhaul or network interface 382 allows the eNB 102to communicate with other devices or systems over a backhaul connectionor over a network. The interface 382 could support communications overany suitable wired or wireless connection(s). For example, when the eNB102 is implemented as part of a cellular communication system (such asone supporting 5G, LTE, or LTE-A), the interface 382 could allow the eNB102 to communicate with other eNBs over a wired or wireless backhaulconnection. When the eNB 102 is implemented as an access point, theinterface 382 could allow the eNB 102 to communicate over a wired orwireless local area network or over a wired or wireless connection to alarger network (such as the Internet). The interface 382 includes anysuitable structure supporting communications over a wired or wirelessconnection, such as an Ethernet or RF transceiver.

The memory 380 is coupled to the controller/processor 378. Part of thememory 380 could include a RAM, and another part of the memory 380 couldinclude a Flash memory or other ROM. In certain embodiments, a pluralityof instructions, such as a BIS algorithm is stored in memory. Theplurality of instructions are configured to cause thecontroller/processor 378 to perform the BIS process and to decode areceived signal after subtracting out at least one interfering signaldetermined by the BIS algorithm.

As described in more detail below, the transmit and receive paths of theeNB 102 (implemented using the RF transceivers 372 a-372 n, TXprocessing circuitry 374, and/or RX processing circuitry 376) supportcommunication with aggregation of FDD cells and TDD cells.

Although FIG. 3B illustrates one example of an eNB 102, various changesmay be made to FIG. 3B. For example, the eNB 102 could include anynumber of each component shown in FIG. 3. As a particular example, anaccess point could include a number of interfaces 382, and thecontroller/processor 378 could support routing functions to route databetween different network addresses. As another particular example,while shown as including a single instance of TX processing circuitry374 and a single instance of RX processing circuitry 376, the eNB 102could include multiple instances of each (such as one per RFtransceiver).

A communication system includes a downlink (DL) that conveys signalsfrom transmission points such as base stations or eNBs to UEs and anuplink (UL) that conveys signals from UEs to reception points such aseNBs. A UE, also commonly referred to as a terminal or a mobile station,may be fixed or mobile and may be a cellular phone, a personal computerdevice, or an automated device. An eNB, which is generally a fixedstation, may also be referred to as an access point or other equivalentterminology.

DL signals include data signals conveying information content, controlsignals conveying DL control information (DCI), and reference signals(RS) that are also known as pilot signals. An eNB transmits datainformation or DCI through respective physical DL shared channels(PDSCHs) or physical DL control channels (PDCCHs). The PDCCH can be anenhanced PDCCH (EPDDCH) but the term PDCCH will be used for brevity todenote PDCCH or EPDCCH. A PDCCH is transmitted over one or more controlchannel elements (CCEs). An eNB transmits one or more of multiple typesof RS including a UE-common RS (CRS), a channel state information RS(CSI-RS), and a demodulation RS (DMRS). A CRS is transmitted over a DLsystem bandwidth (BW) and can be used by UEs to demodulate data orcontrol signals or to perform measurements. To reduce CRS overhead, aneNB can transmit a CSI-RS with a smaller density in the time and/orfrequency domain than a CRS. For channel measurement, non-zero powerCSI-RS (NZP CSI-RS) resources can be used. For interference measurementreports (IMRs), CSI interference measurement (CSI-IM) resourcesassociated with zero power CSI-RS (ZP CSI-RS) resources can be used [3].A CSI process consists of NZP CSI-RS and CSI-IM resources. DMRS istransmitted only in the BW of a respective PDSCH and a UE can use theDMRS to demodulate information in a PDSCH.

UL signals also include data signals conveying information content,control signals conveying UL control information (UCI), and RS. A UEtransmits data information or UCI through a respective physical ULshared channel (PUSCH) or a physical UL control channel (PUCCH). When aUE simultaneously transmits data information and UCI, the UE canmultiplex both in a PUSCH or the UE can transmit data and some UCI in aPUSCH and transmit remaining UCI in a PUCCH when the eNB configures theUE for simultaneous PUSCH and PUCCH transmission. UCI includes hybridautomatic repeat request acknowledgement (HARQ-ACK) information,indicating correct or incorrect detection of data transport blocks (TBs)in a PDSCH, scheduling request (SR) indicating whether a UE has data inits buffer, and CSI enabling an eNB to select appropriate parameters forlink adaptation of PDSCH or PDCCH transmissions to a UE.

CSI includes a channel quality indicator (CQI) informing an eNB of a DLsignal to interference and noise ratio (SINR) experienced by the UE, aprecoding matrix indicator (PMI) informing an eNB how to applybeam-forming for DL transmissions to the UE, and a rank indicator (RI)informing the eNB of a rank for a PDSCH transmission. UL RS includesDMRS and sounding RS (SRS). A UE transmits DMRS only in a BW of arespective PUSCH or PUCCH and an eNB can use a DMRS to demodulateinformation in a PUSCH or PUCCH. A UE transmits SRS to provide an eNBwith an UL CSI. A SRS transmission from a UE can be periodic (P-SRS, ortrigger type 0 SRS) or aperiodic (A-SRS, or trigger type 1 SRS) astriggered by a SRS request field included in a DCI format conveyed by aPDCCH scheduling PUSCH or PDSCH.

A transmission time interval (TTI) for DL transmission or for ULtransmission is referred to as a subframe (SF) and includes two slots. Aunit of ten SFs is referred to as a system frame. A system frame isidentified by a system frame number (SFN) ranging from 0 to 1023 and canbe represented by 10 binary elements (or bits). A BW unit for a DLtransmission or for an UL transmission is referred to as a resourceblock (RB), one RB over one slot is referred to as a physical RB (PRB),and one RB over one SF is referred to as a PRB pair. Each RB consists ofN_(sc) ^(RB) sub-carriers, or resource elements (REs). A RE isidentified by the pair of indexes (k,l) where k is a frequency domainindex and l in a time domain index. An eNB informs parameters for aPDSCH transmission to a UE or parameters for a PUSCH transmission fromthe UE, through a DCI format with CRC scrambled by a cell radio networktemporary identifier (C-RNTI), that is conveyed in a PDCCH the eNBtransmits to the UE and is respectively referred to as DL DCI format orUL DCI format.

A communication system includes a downlink (DL) that conveys signalsfrom transmission points such as base stations (BSs) or NodeBs to userequipments (UEs) and an uplink (UL) that conveys signals from UEs toreception points such as NodeBs. Additionally a sidelink (SL) may conveysignals from UEs to other UEs or other non-infrastructure based nodes. AUE, also commonly referred to as a terminal or a mobile station, may befixed or mobile and may be a cellular phone, a personal computer device,etc. A NodeB, which is generally a fixed station, may also be referredto as an access point or other equivalent terminology such as eNodeB.The access network including the NodeB as related to 3GPP LTE is calledas E-UTRAN (Evolved Universal Terrestrial Access Network).

In a communication system, DL signals can include data signals conveyinginformation content, control signals conveying DL control information(DCI), and reference signals (RS) that are also known as pilot signals.A NodeB transmits data information through a physical DL shared channel(PDSCH). A NodeB transmits DCI through a physical DL control channel(PDCCH) or an enhanced PDCCH (EPDCCH). Messages are transmitted on thePDCCH using a cell radio network temporary identifier (C-RNTI) toidentify the intended UE. The C-RNTI is the RNTI to be used by a givenUE while the UE is in a particular cell after the UE and a NodeBestablish an RRC connection. A NodeB transmits one or more of multipletypes of RS including a UE-common RS (CRS), a channel state informationRS (CSI-RS), or a DeModulation RS (DMRS). A CRS is transmitted over a DLsystem bandwidth (BW) and can be used by UEs to obtain a channelestimate to demodulate data or control information or to performmeasurements. To reduce CRS overhead, a NodeB may transmit a CSI-RS witha smaller density in the time and/or frequency domain than a CRS. DMRScan be transmitted only in the BW of a respective PDSCH or EPDCCH and aUE can use the DMRS to demodulate data or control information in a PDSCHor an EPDCCH, respectively. A transmission time interval for DL channelsis referred to as a sub-frame (SF) and can have, for example, durationof 1 millisecond. A number of ten SFs is referred to as a frame and isidentified by a system frame number (SFN).

Traditionally, cellular communication networks have been designed toestablish wireless communication links between mobile devices (UEs) andfixed communication infrastructure components (such as base stations oraccess points) that serve UEs in a wide or local geographic range.However, a wireless network can also be implemented by utilizing onlydevice-to-device (D2D) communication links without the need for fixedinfrastructure components. This type of network is typically referred toas an “ad-hoc” network. A hybrid communication network can supportdevices that connect both to fixed infrastructure components and toother D2D-enabled devices. While UEs such as smartphones can beenvisioned for D2D networks, vehicular communication can also besupported by a communication protocol where vehicles exchange control ordata information with other vehicles or other infrastructure or UEs.Such a network is referred to as a V2X network. Multiple types ofcommunication links can be supported by nodes supporting V2X in thenetwork and can utilize same or different protocols and systems.

FIG. 4 illustrates an example use case of a vehicle-centriccommunication network according to illustrative embodiments of thepresent disclosure.

The vehicular communication, referred to as Vehicle-to-Everything (V2X),contains the following three different types: Vehicle-to-Vehicle (V2V)Communications, Vehicle-to-Infrastructure (V2I) Communications, andVehicle-to-Pedestrian (V2P) Communications. These three types of V2X canuse “co-operative awareness” to provide more intelligent services forend-users. This means that transport entities, such as vehicles,roadside infrastructure, and pedestrians, can collect knowledge of theirlocal environment (e.g., information received from other vehicles orsensor equipment in proximity) to process and share that knowledge inorder to provide more intelligent services, such as cooperativecollision warning or autonomous driving.

V2X communication can be used to implement several types of servicesthat are complementary to a primary communication network or to providenew services based on a flexibility of a network topology. V2X cansupport unicasting, broadcasting, or group/multicasting as potentialmeans for V2V communication 400 where vehicles are able to transmitmessages to all in-range V2V-enabled devices or to a subset of devicesthat are members of particular group. The protocol can be based onLTE-D2D or on a specialized LTE-V2V protocol. V2X can support V2Icommunication 401 between one or more vehicles and an infrastructurenode to provide cellular connectivity as well as specialized servicesrelated to control and safety of vehicular traffic. V2P communication402 can also be supported, for example to provide safety services forpedestrians or traffic management services. V2X multicast communication403 can be used to provide safety and control messages to large numbersof vehicles in a spectrally efficient manner. The two primarystandardized messages for V2V/V2I communication are the periodic beaconscalled Cooperative Awareness Messages (CAM) and the event-triggeredwarning messages, called Decentralized Environment Notification Messages(DENM). The CAMs are periodically broadcasted beacons used to maintainawareness of the surrounding vehicles. These messages are sent with anadaptive frequency of 1-10 Hz. The CAMs include information such asposition, type and direction.

The CAM generation triggers the following two conditions.

1. The time elapsed since the last CAM generation is equal to or greaterthan a minimum value and one of the following UE-dynamics relatedconditions is given: a. the absolute difference between the currentheading of the originating UE and the heading included in the CAMpreviously transmitted by the originating UE exceeds 4°; b. the distancebetween the current position of the originating UE and the positionincluded in the CAM previously transmitted by the originating UE exceeds4 m; and c. the absolute difference between the current speed of theoriginating UE and the speed included in the CAM previously transmittedby the originating UE exceeds 0.5 m/s.

2. The time elapsed since the last CAM generation is equal to or greaterthan a maximum value.

If one of the above two conditions is satisfied, a CAM shall begenerated immediately. Thus, CAM messages generation times and sizes arenot completely deterministic from a traffic modeling perspective.Nevertheless, the typical time difference between consecutive packetsgeneration is bounded to the [0.1, 1] sec range.

The DENMs are event-triggered warning messages which are generated toalert neighboring vehicles about potential hazards.

While vehicle devices can be able to support many differentcommunication protocols and include support of mandatory or optionalfeatures, since the traffic types, QoS requirements, and deploymenttopologies are distinct from other types of communications, thehardware/software on a vehicle for supporting V2X can have a reduced orspecialized functionality compared to other devices. For example,protocols related to low-complexity, low-data rate, and/or low-latencyfor machine-type communications 404 can be supported such as, forexample, traffic tracking beacons. Satellite-based communication 405 canalso be supported for V2X networks for communication or positioningservices.

Direct communication between vehicles in V2V is based on a sidelink (SL)interface. Sidelink is the UE to UE interface for SL communication andSL discovery. The SL corresponds to the PC5 interface as defined in REF6. SL communication is defined as a functionality enabling proximityservices (ProSe) Direct Communication as defined in REF 6 between two ormore nearby UEs using E-UTRA technology but not traversing any networknode.

E-UTRAN allows such UEs that are in proximity of each other to exchangeV2V-related information using E-UTRA(N) when permission, authorizationand proximity criteria are fulfilled. The proximity criteria can beconfigured by the MNO. However, UEs supporting V2V Service can exchangesuch information when served by or not served by E-UTRAN which supportsV2X Service. The UE supporting V2V applications transmits applicationlayer information (e.g. about its location, dynamics, and attributes aspart of the V2V Service). The V2V payload must be flexible in order toaccommodate different information contents, and the information can betransmitted periodically according to a configuration provided by theMNO. V2V is predominantly broadcast-based; V2V includes the exchange ofV2V-related application information between distinct UEs directlyand/or, due to the limited direct communication range of V2V, theexchange of V2V-related application information between distinct UEs viainfrastructure supporting V2X Service, e.g., RSU, application server,etc.

FIG. 5 illustrates an example SL interface according to illustrativeembodiments of the present disclosure. The embodiments shown in FIG. 5are for illustration only. Other embodiments could be used withoutdeparting from the scope of the present disclosure.

While UL designates the link from UE 501 to NodeB 503 and DL designatesthe reverse direction, SL designates the radio links over the PC5interfaces between UE 201 and UEs 502. UE 501 transmits a V2V message tomultiple UEs 502 in the SL. SL communication happens directly withoutusing E-UTRAN technology and not traversing any network node NodeB 503.The PC5 interface re-uses existing frequency allocation, regardless ofthe duplex mode (frequency division duplex (FDD) or time division duplex(TDD). To minimize hardware impact on a UE and especially on the poweramplifier of the UE, transmission of V2V links occurs in the UL band incase of FDD. Similar, the PC5 interface uses SFs that are reserved forUL transmission in TDD. The signal transmission is based on singlecarrier frequency division multiple access (SC-FDMA) that is also usedfor UL transmission. The new channels can be largely based on thechannel structure applicable for the transmission of the physical ULshared channel (PUSCH).

SL transmission and reception occurs with resources assigned to a groupof devices. A resource pool (RP) is a set of resources assigned forsidelink operation. It consists of the subframes and the resource blockswithin the subframe. For SL communication, two additional physicalchannels are introduced: Physical Sidelink Control Channel (PSCCH)carrying the control information, and Physical Sidelink Shared Channel(PSSCH) carrying the data.

FIG. 6 illustrates an example resource pool for PSCCH according toillustrative embodiments of the present disclosure.

The pool is defined as follows. (a) in frequency: by parameters, PRBnumthat defines the frequency range in Physical Resource Block (PRB)bandwidth units; and PRBstart and PRBend, which define the location inthe frequency domain within the uplink band; and (b) in the time domain:by a bitmap that indicates the 1 msec sub-frames used for PSCCHtransmission.

This block of resources is repeated with a period defined by a parameterSC-Period (expressed in sub-frame duration, i.e. 1 msec). The range ofpossible values for SC-Period is from 40 msec to 320 msec: low valuesare supported for voice transmission.

All the parameters needed to define the resource pool are broadcasted ina System Information Block (SIB) by the network. The devices which arenot within coverage (and hence cannot acquire the SIB) shall use somepre-configured values internally stored. The PSCCH is used by the D2Dtransmitting UE to make the members of its group aware of the next datatransmission that will occur on the PSSCH. The D2D transmitting UE sendsthe sidelink control information (SCI) on the PSCCH as shown in TABLE 1.

TABLE 1 Parameter Usage Group Destination ID used by the receivingdevices to determine whether they have some interest in thisannouncement. If the identifier does not match, they do not need tomonitor sidelink channels until the next SC-Period Modulation and CodingTo indicate modulation and coding rate for the data Scheme Resourceblock give the receiving devices information about the resources of theassignment and hopping PSSCH that they shall decode in the frequencydomain resource allocation Frequency hopping flag Time Resource Patterngive the receiving devices information about the resources of the(T-RPT) PSSCH that they shall decode in the time domain Timing advance

Devices interested in receiving D2D services blindly scan the wholePSCCH pool to search if a SCI format matching their group identifier canbe detected. On the transmitting device side, resources to transmit theSCI format information shall be selected within the PSCCH pool.

There are two types of resource pools: Reception Resource Pools (Rx RPs)and Transmission Resource Pools (Tx RPs). These are either signaled bythe NodeB for in-coverage case or a pre-configured value is used for theout-of-coverage case. Within a cell, there may be more Rx RPs than TxRPs to enable reception from adjacent cells or from out-of-coverage UEs.

Two modes of resource allocation have been defined for SL communication:Mode 1, also referred as “Scheduled resource allocation” and Mode 2,also referred as “UE autonomous resource selection”

In mode 1, access to the sidelink resources is driven by the NodeB. TheUE needs to be connected to transmit data in the following three cases.

The UE wishing to use direct communication feature sends an indicationto the network. It will be assigned a temporary identifier SL-RNTI(Sidelink Radio Network Temporary Identifier). This identifier will beused by the eNodeB to schedule the future D2D transmission.

When the UE has some data to transmit in D2D mode, it sends asidelink-BSR (Buffer Status Report) to the eNodeB which gives anindication on the amount of data to be transmitted in D2D mode. Based onthis information, the eNodeB sends to the UE the allocation on bothPSCCH and PSSCH for its D2D transmission. The allocation information issent over the PDCCH (Physical Downlink Control Channel) by sending a DCIFormat 5, scrambled by the SL-RNTI. The information contained in DCIformat 5 is detailed in Table 2. A large part of the DCI Format 5information is directly reflected in the content of the SCI format 0.

Based on the information received in the DCI format 5, the D2Dtransmitting devices sends the SCI format 0 over the resources withinthe PSCCH pool allocated by the eNodeB, followed by the data over theresources allocated by the eNodeB for PSSCH transmission.

TABLE 2 Parameter Bits Usage Resource for PSCCH 6 Provides theinformation of the transmitting UE of the resource to be used for SCIformat 0 transmissions within the PSCCH pool. TPC command 1 If this bitis not set, the transmitting UE is allowed to transmit D2D signals atmaximum power. Otherwise, it shall comply with power control rules basedon open loop. Resource block assignment 5-13 give to the receivingdevices the information of the resources and hopping resource of thePSSCH that they shall decode in the frequency domain allocationFrequency hopping flag 1 Time Resource Pattern 7 give to the receivingdevices the information of the resources (T-RPT) of the PSSCH that theyshall decode in the time domain

In mode 1, there is no pre-allocated or reserved resource for PSSCH: itis assigned “on-demand” by the NodeB. In addition, since the NodeB isresponsible to give access to the resources within the PSCCH pool,collision on the PSCCH transmission can be avoided.

In mode 2, the UE transmitting D2D data does not need to be connected tothe eNodeB: it selects autonomously and randomly the resources withinthe PSCCH pool to transmit the SCI Format 0.

In addition to the PSCCH pool, there is also a PSSCH pool which definesreserved resources for PSSCH transmission. It is defined in a similarway as the PSCCH pool (PRBStart, PRBend, PRBNum in the frequency domainand a sub-frame bitmap in the time domain which is repeated up to thenext PSCCH occurrence). The SCI Format 0 designates the portion of thepool that is used for D2D transmission. Since the transmitting UE is notnecessarily connected to the NodeB, the timing advance information maybe not known and the corresponding parameter in the SCI Format 0 shallbe set to 0.

FIG. 7 illustrates an example subframe resource allocation according toillustrative embodiments of the present disclosure. The embodimentsshown in FIG. 7 are for illustration only. Other embodiments could beused without departing from the scope of the present disclosure.

The subframe bitmap discussed in FIG. 6 is split into two regions:control region and data region. The first SC Period starts at an offsetfrom SFN=0 and is periodically repeated with a configurable lengthbetween 40 msec and 320 msec. It starts with the control region whichcontains the SCI0 control element carried by the PSCCH. SubframeBitmapSLindicates the subframes used for the PSCCH. Directly after the last bitof the SubframeBitmapSL which is set to 1, the data region starts. Itconsists of another bitmap, the T-RPT bitmap, which is a bitmapindicating the subframes which are used for the data transmission. Thisbitmap is repeated until the end of the SC Period, where the lastoccurrence may be truncated.

The T-RPT bitmap is dynamic and may therefore be different for each UEand for each SC Period. To be more precise, the set of all subframeswhich are allocated for the resource pool is restricted by using aperiodic pattern with a periodicity of 8 for FDD, and a shorter one forsome TDD configurations. Necessary parameters to determine this bitmapin order to receive the data part are signaled via the PSCCH.

For Mode 2, this structure is quite similar. The main difference is thatstart of the data part does not depend on the content of theSubframeBitmapSL, but has a fixed offset from the start of the SCPeriod. In addition, the algorithm to determine the bitmap pattern issomewhat different and may explicitly exclude some configurations.

Semi-persistent scheduling (SPS) is available for DL/UL communication inLTE, primarily to support voice. Since the PDCCH is limited size(generally, 3 OFDM symbols), there is a limit as to how many DCIs can becarried in a subframe. This can in-turn limits the number of UEs whichcan receive an allocation for that subframe when using dynamicscheduling (a 1:1 PDCCH-to-PxSCH method). With SPS, the UE ispre-configured by the eNB with an SPS-RNTI (allocation ID) and aperiodicity. Once pre-configured, if the UE were to receive anallocation (DL/UL) using the SPS-RNTI (instead of the typical C-RNTI),then this one allocation would repeat according to the pre-configuredperiodicity.

During SPS, certain parameters remain fixed for each allocation: RBassignments, Modulation and Coding Scheme, etc. Because of this, if theradio link conditions change, a new allocation will have to be sent(PDCCH). SPS can be configured/re-configured by RRC at any time usingSPS-Config.

This SPS-Config includes the configuration for semiPersistSchedC-RNTI(sps-CRNTI), sps-ConfigDL and sps-ConfigUL. SPS can be configured onlyin the uplink (sps-ConfigUL), or in the downlink (sps-ConfigDL) or inboth directions. Configuration of SPS doesn't mean that the UE can startusing SPS grants/assignments. The eNB has to explicitly activate SPS, inorder for the UE to use SPS grants/assignments.

Also, to avoid wasting resources when a data transfer is completed,there are several mechanisms for deactivating SPS (explicit, inactivitytimer, etc.). When configuring SPS in any direction either UL or DL, SPSC-RNTI is mandatorily provided by the eNB. Soon after the UE isconfigured with SPS C-RNTI, the UE is configured by higher layers todecode PDCCH with CRC scrambled by the SPS C-RNTI. A UE shall monitorPDCCH with CRC scrambled by the SPS C-RNTI in every subframe as the eNBcan activate/re-activate/release SPS at any time using Downlink controlinformation (DCI).

There is a need to support semi-persistent transmissions for V2Xcommunications for the following reasons. There is a requirement thatthe E-UTRA(N) shall be capable of transferring periodic broadcastmessages between two UEs supporting V2X Services with variable messagepayloads of 50-300 bytes, not including security-related messagecomponent. For many V2V data services, the message sizes are small andthe inter-arrival time of transmission is fairly constant (for example,the CAM messages are periodic with frequency of 1-10 Hz). The controlsignaling overhead (PSCCH and/or PUCCH) can be significant in order tosupport a large number of vehicles. So, it is important to allocate theresources at once and let the vehicle use these resources instead ofre-allocating the resources periodically. To support this efficiently,semi-persistent scheduling support is desirable for V2X communication.Although the CAM traffic is approximately periodic for relatively longintervals or in proximity of certain events, it is necessary to takeinto account the possible deviations when designing semi-persistenttransmissions in the LTE V2X framework.

SPS is not supported in SL communication using Rel-13. The PSCCHtransmissions need to be enhanced to support SPS. Furthermore, multipleSPS configurations for a given UE can be supported.

The present disclosure considers semi-persistent transmissions on boththe SL (under mode 1 and mode 2) as well as the UL.

FIG. 8 shows an example of CAM message periodicity as a function of UEspeed according to the embodiments of this disclosure. The embodimentsshown in FIG. 8 are for illustration only. Other embodiments could beused without departing from the scope of the present disclosure.

CAM messages 801 are generated between 1-10 messages per second based onthe speed of the UE. However, it is likely that UEs in a given locationshare similar speeds, based on speed limits and the traffic in thatlocation. Thus, the eNodeB can configure different periodicity of theCAM message reports from the UE based on the geo location of thetransmitting UE. For example, the eNodeB can configure vehicles in thefreeway to transmit their CAM messages more frequently, say every 100ms, compared to vehicles on the side streets, who may be requested totransmit every 500 ms, for example.

As a vehicle moves, its speed may vary in a few seconds (which is stillslow compared to the communication time period) and over time, theperiodicity P of the CAM message transmissions from the UE will change.This will cause empty allocations and can lead to inefficient usage ofresources as the vehicle speed changes. If a fixed period is assigned tothe UE for SPS, either the period has to be dynamically updated ortechniques to improve resource efficiency have to be considered.Furthermore, the message size may also change when additional CAMinformation such as security information may be transmitted. Thus,dynamic variation of both CAM message periodicity and message size needsto be considered in the SPS design for V2X.

FIG. 9 illustrates an example of the semi-persistent CAM messagestransmitted by the vehicle UE to the eNodeB (eNB) on the UL or to otherUEs on the SL, according to the embodiments of this disclosure. Theembodiments shown in FIG. 9 are for illustration only. Other embodimentscould be used without departing from the scope of the presentdisclosure.

The vehicle transmits CAM messages which are triggered by externalconditions, depending on the originating UE dynamics such as UE speed asshown in FIG. 8 and the channel congestion status. FIG. 9 shows anexample where the periodicity can be reducing dynamically in a freewayas the vehicle UE goes from a fast speed 901 (140 km/hr, for example) toa medium speed 903 (40 km/hr) to a slow speed 904 (10 km/hr) due totraffic conditions. The CAM messages, if transmitted, are sent based ona semi-persistent allocation and use resource blocks of size N_(RB) withperiodicity P, where P can be for example, 100 ms. Even in a given area,with speed or direction variations for a given vehicle UE, there may begaps in the transmission such as 903, where no message is transmitted,for example, when the distance between the current position of thetransmitting UE and the position included in the CAM previouslytransmitted by the UE is less than 4 m.

In one embodiment of this disclosure, the eNodeB configures theperiodicity P for the vehicle UE for semi-persistent transmissions basedon the geographical information of the UE and/or the driving speedlimits set in that geographical location. For example, vehicle UEs onthe freeway or platooning for autonomous vehicles can use a periodicityof traffic generation of P=100 ms, while vehicle UEs on the side streetsin a different geographical location can use a periodicity of P=300 ms.

Allocation of SPS Resources by the eNB

In embodiments of the present disclosure, exclusive resources areallocated by the eNodeB for semi-persistent transmissions. These emptyallocations can lead to inefficient usage of resources as the vehiclespeed decreases, for example. The CAM message size can also change suchas from 901 to 902 when additional CAM information such as securityinformation may be transmitted.

Dynamic adaptation of SPS periodicity based on UE speed, directionchange, etc. can have high overhead for the eNodeB (for mode 1 SL and/orUL SPS operation) and can cause significant resource allocationadjustments.

In one embodiment, the eNodeB (eNB) allocates shared SPS resources forsemi-persistent transmissions from multiple vehicle UEs. Multiplevehicle UEs can share a common set of SPS resources. In anotherembodiment of this disclosure, a shared resource allocation with aperiodicity of 100 ms, for example, is configured by the eNodeB forsemi-persistent transmissions from multiple vehicle UEs.

FIG. 10 shows an example of a shared resource allocation for ULsemi-persistent transmissions according to the embodiments of thisdisclosure. The embodiments shown in FIG. 10 are for illustration only.Other embodiments could be used without departing from the scope of thepresent disclosure.

The resource allocation for semi-persistent transmissions 1001 is sharedbetween vehicle UEs 1002, 1003, 1004 in this example. Multiple vehicleUEs can share a common set of SPS resources.

Random Resource Allocation

In one embodiment, the vehicle UEs randomly select at least one of theresources within the shared resource allocation for transmitting eachCAM message. While this may lead to occasional collisions as shown in1005, it can provide improved efficiency of resource usage. Since CAMmessages contain location information etc. that assist resourceallocation and are transmitted frequently, the reliability of thesemessages is not as critical as DENM messages i.e. loss of occasional CAMmessages may be acceptable.

Periodicity Based SPS Resource Allocation

In another embodiment of the present disclosure, the resources areselected in the shared SPS resource pool based on the dynamicperiodicity of CAM message transmissions. In periodicity basedallocation, SPS messages from multiple UEs are multiplexed on the sameSPS resource based on message periodicity. i.e. transmitting UE tries tomultiplex UEs, if possible, in a given resource allocation while aimingto minimize overlaps for possible collisions.

FIG. 11 shows an example embodiment of this disclosure, where theresources are allocated in the shared set according to dynamicperiodicity (due to speed changes, for example). The embodiments shownin FIG. 11 are for illustration only. Other embodiments could be usedwithout departing from the scope of the present disclosure.

The UE changes its selected resource for UL transmission if there is achange in periodicity of the CAM message transmission (due to change inspeed/direction etc.). For slower speed UEs, as shown by UE-3 1103 forexample, the periodicity of CAM message transmissions is larger and thatmeans more slow speed UEs can be multiplexed in the same resourceallocation.

In some embodiments, UE-2 1102 and UE-4 1104, which have the sameperiodicity can be multiplexed into the same set of resources in timebut being offset by the periodicity P (=100 ms, in this embodiment). Ifthe speed of UE-4 1104 decreases at a later time, it changes itsresource allocation and finds another set of resources or vehicles toget multiplexed with.

In embodiments of the present disclosure, where sufficient resourcesexist, multiple shared resources can be configured for SPStransmissions, each supporting a different periodicity, which areselected based on the current periodicity of the CAM messagetransmissions for a given vehicle UE.

Since the SPS resources are not exclusive to a UE, there is now a needto send control information in the first few symbols of the SF, forexample, followed by the message. The UEs can transmit controlinformation formats to inform the eNB or other UEs of transmissionparameters for subsequent reception. This method allows the UE to usedifferent MCS/TBS and possibly different RBs depending on its SINR ordata TBS it needs to convey. The RBs in the shared SPS resources can beconfigured by the eNB using RRC, for example or could be based onsensing. Even the subframes where the RBs are available can beconfigured by the eNB (i.e. if some latency can be tolerated, theSFs/frames for UE-initiated transmissions can be configured and need notbe the same every SF). When the UE has data to transmit, the UE sendscontrol information about the data transmission (such as UE ID, MCS, RBsfrom the configured RBs, etc.). In some embodiments, a search space isused so that the eNB does not have too many hypotheses to check for thecontrol information, (e.g. control can be sent in a finite number ofcombinations of RBs within the configured set of RBs). In otherembodiments, the control can be transmitted in more than one location inthe shared set of resources, which can reduce combined probability ofcollision. In yet other embodiments, the control could be transmitted ina reserved region in the set of shared resources, while only the data isshared in the shared resources. The benefit of this approach is that itprovides RB and MCS adaptation while supporting semi-persistenttransmissions with improved resource management.

A UE can thus, be configured to support semi-persistent transmissionsfor UL/DL and SL transmissions.

Semi-Persistent Transmissions on the Sidelink

CAM messages are also transmitted on the SL for both mode 1 and mode 2operation. In addition, the SPS transmissions on SL may be repeatedmultiple times (within a frame or subframe, for example), to supporthalf-duplex transmissions. This will allow other UEs who are alsotransmitting at the same time to be able to receive the messages at adifferent time instance.

Mode 1 Operation

SPS Configuration

Multiple SPS configurations can be configured for a given UE. Theconfigurations can support multiple periodicities, multiple RB sizes andMCS for a given UE.

Multiple SL SPS configurations can be used to handle the periodicityvariation for the basic message transmission. In this case, onlyswitching between multiple SL SPS configurations is needed and only 1 SLSPS configuration needs to be active at a given time. The additionalmessages may either be configured using SPS with a differentperiodicity, if possible, or may be dynamically scheduled by the eNB. Inthis case, multiple SPS configurations for SL are actively running at agiven time.

To support the dynamic variation for V2V messages, it is proposed tohave two types of SPS configurations: Type-1 SPS configuration: wheremessages are of the same allocation, MCS and periodicity; and Type-2 SPSconfiguration: where messages of different allocation, MCS andperiodicity are multiplexed within same configuration. Either multipleSPS configurations of Type 1 or a single configuration of Type 2 can besupported at a given time for a UE.

FIG. 12 shows an example design of SPS configuration types according tothe embodiments of this disclosure. The embodiments shown in FIG. 12 arefor illustration only. Other embodiments could be used without departingfrom the scope of the present disclosure.

A Type-1 SPS configuration is defined by a combination of MCS, resourceblocks (RB) and periodicity (P). A type-2 SPS configuration is definedby a combination of multiple MCS, resource blocks and periodicitiesalong with offsets (K) which indicates the relative offset of theperiodicity of the multiple configuration with respect to the firstconfiguration. These configurations are supported by RRC signaling. Tosupport dynamic variation in V2X messages, multiple SPS processes of agiven type can be active for the UE.

The SPS is configured via RRC signaling. The SPS can be changeddynamically by the eNB based on UE UL transmissions, for example,indication of a zone change, speed change and/or priority, based onmessages sent in the PUSCH. The SPS change can also be based on ascheduling request from the UE, for example, indicated in the PUCCH.

In embodiments of the present disclosure, the SPS configuration is splitinto 2 parts: SPS-Config-Common-UE which has the common parametersacross configurations for the UE and includes at least SPS SL-RNTI; andSPS-Config-Specific-UE which has each SPS configuration-specificparameters for the UE and includes at least: Scheduling interval (inmultiples of sub-frames); Activation sub-frame offset: The sub-frameoffset at which this SPS will start after activation; SPS-ConfigurationID: Unique identifier for this SPS configuration; Implicit releaseafter; MCS (modulation, coding rate); and Resource blocks.

It is proposed that a common SPS RNTI be used for SL across multiple SPSconfigurations. It is proposed that a unique SPS configuration ID forevery SPS configuration can be provided to the UE as part of the RRCconfiguration. Another option is that the UE implicitly assumes SPSconfiguration IDs based on the order in which the UE-specificconfigurations are configured by the RRC. Since only 1 SPS can beactivated in a SF using DCI/PDCCH, the sub-frame offset for activationis indicated as part of the configuration. The MCS and resource blockscan be indicated as part of the DCI in the PDCCH.

In embodiments of the present disclosure, multiple SPS configurationsare used (there is no common configuration). SPS-Config-Specific-UEwhich has each SPS configuration-specific parameters for the UE andincludes at least (i) RRC: SPS SL-RNTI; Scheduling interval (inmultiples of sub-frames); Activation sub-frame offset: The sub-frameoffset at which this SPS will start after activation; SPS-ConfigurationID: Unique identifier for this SPS configuration; and Implicit releaseafter, and (ii) DCI/PDCCH: MCS (modulation, coding rate); and Resourceblocks.

In one embodiment, it is proposed that each SPS is distinguished by adifferent RNTI. It is proposed that a unique SPS configuration ID forevery SPS configuration can be provided to the UE as part of the RRCconfiguration. Another option is that the UE implicitly assumes SPSconfiguration IDs based on the order in which the UE-specificconfigurations are configured by the RRC or the SPS configuration IDsare assigned based on sorting of a configuration parameter such as RNTI.Since only 1 SPS can be activated in a SF using DCI/PDCCH, the sub-frameoffset for activation is indicated as part of the configuration. The MCSand resource blocks can be indicated as part of the DCI in the PDCCH.

It is proposed that the maximum number of simultaneous SPSconfigurations for a UE be limited to 4.

FIG. 13 shows the SPS operation for Mode 1 operation, where the UE has asingle SPS process at a given time, but can switch between multiple SPSprocesses, according to the embodiments of this disclosure. Theembodiments shown in FIG. 13 are for illustration only. Otherembodiments could be used without departing from the scope of thepresent disclosure.

The eNB first configures a common SPS configuration for the UE, such asSL RNTI, (if used). Based on the traffic type (which requires SPS config1), the UE can request a specific SPS configuration for SL in step 1305.This request can be made via a scheduling request on the PUCCH, forexample. Alternately, the eNB can determine the SL SPS configurationbased on the UE reporting of geo-information, speed and the like. The UEreporting can be done by transmission of a CAM message on the PUSCH, forexample. In step 1310, the eNB then configures the specific SPSconfiguration (Config 1) parameters such as periodicity, using RRC, forexample. In step 1315, the eNB then activates the SPS configuration(Config 1) via DCI on the (E)PDCCH. When the traffic type changes(requiring SPS Config 2) and is known to the eNB via a schedulingrequest or by CAM messages, the eNB configures another SPS (Config 2)for the UE in step 1320, without terminating the first SPS (Config 1)via RRC, for example. The eNB then releases the first configuration(Config 1) and activates the second (Config 2) in step 1325. When thetraffic type changes again to traffic type 1, no new RRC configurationis needed for Config 1 and the eNB can directly release Config 2 andactivate Config 1 in step 1330. The SPS can also be implicitly releasedif the number of “no data” transmissions exceeds a threshold set by theeNB.

FIG. 14 shows the SPS operation for Mode 1 operation where the UE hassimultaneous SPS processes running in parallel, according to theembodiments of this disclosure. The embodiments shown in FIG. 14 are forillustration only. Other embodiments could be used without departingfrom the scope of the present disclosure.

The eNB first configures a common SPS configuration for the UE, such asSL RNTI in step 1401. Based on the traffic type (requiring SPS Config 1and SPS Config 2), the UE can request multiple specific SPSconfigurations for SL.

Scheduling Request (SR) Enhancement for Multiple SPS

The UE provides periodic reports to the eNB by configuring a reportingSPS on the UL. Based on the UE reports, the eNB may configure the UEwith one or more SPS transmissions for SL. The scheduling request on theUL should be enhanced to request one of multiple SPS configurations. TheUE request can be made via a scheduling request on the PUCCH, forexample. Currently, the SR has only 1 bit for indicating the SPSrequest. SR currently uses a simple ON-OFF keying scheme, where the UEtransmits a SR with BSPK modulation symbol d(0)=+1 to request a PUSCHresource and transmitting nothing if it does not request to bescheduled.

If there are multiple SPS configurations, for example, up to a maximumof 4 configurations, two bits could be used in the SR to indicate theconfiguration. In this case, an ON-OFF keying scheme can still be used,but with QPSK modulation symbols instead of BPSK, with eachconfiguration indicated by one of the 4 constellation points of QPSKmodulation, to request a PUSCH resource and transmitting nothing if itdoes not request to be scheduled. Table 3 shows an example of the SRusing QPSK modulation, assuming maximum of 4 SPS configurations areavailable. The SR/PUCCH approach will have smaller latency if theconfiguration is selected by the UE.

TABLE 3 Modulation bits Scheduling Request 00 Request SPS configuration0 01 Request SPS configuration 1 10 Request SPS configuration 2 11Request SPS configuration 3

Alternately, the configuration information can be in transmitted in thePUSCH, especially if the UE does not indicate one of the multipleconfigurations but provides other information for the eNB to determinethe configuration. The eNB can determine the multiple SL SPSconfigurations based on the UE reporting of geo-information, speed etc.The UE reporting can be done by transmission of a CAM message on thePUSCH, for example. In step 1405, the eNB then configures the specificSPS configuration (Config 1 and Config 2) parameters such asperiodicity, using RRC, for example. The eNB then activates the SPSconfiguration (Config 1 and Config 2) via DCI on the (E)PDCCH in step1410. When the traffic type changes (which requires Config 1 and Config3) and is known to the eNB via a scheduling request or by CAM messages,the eNB configures another SPS (Config 3) for the UE in step 1415,without terminating the first two SPS (Config 1 and Config 2) via RRC,for example. The eNB then releases the first configuration (Config 2)and activates the third (Config 3) to support traffic type 2 in step1420. When the traffic type changes again to traffic type 1, no new RRCconfiguration is needed and the eNB can directly release Config 3 andactivate Config 1 in step 1425.

In another embodiment of the disclosure, the UE partitions the messagessuch that the common part is sent using SPS while the non-common(additional messages) are sent using dynamic resources allocated basedon a dynamic scheduling request sent on the PUCCH.

FIG. 15 shows the partitioning of the messages by the UE for SPS andnon-SPS transmissions, based on an embodiment of this disclosure. Theembodiments shown in FIG. 15 are for illustration only. Otherembodiments could be used without departing from the scope of thepresent disclosure.

The UE switches between SPS configurations SPS-1, SPS-2 and SPS-3 inthis example, to change the periodicity of the basic messagetransmissions, while the additional messages are sent in a non-SPSmethod based on dynamic resources allocated by the eNB based on UErequest. Alternately, the additional messages may also be transmittedusing multiple type-1 SPS configurations. It is proposed that the MACfragments the V2X messages into proper (equal) sizes to enable SPStransmissions, as shown in FIG. 15.

FIG. 16 shows the fragmentation of the V2X messages into multipletransport blocks for SPS and transmission on different subframes,according to the embodiments of this disclosure. The embodiments shownin FIG. 16 are for illustration only. Other embodiments could be usedwithout departing from the scope of the present disclosure.

The messages are fragmented to support SPS transmissions with samemessage sizes and RB utilization. At the physical layer, these messagesafter fragmentation are transmitted in different sub-frames so that onlya single transport block (TB) is transmitted on a given subframe. Eachof these transport blocks are part of a different SPS process due totheir different periodicities. A V2X message 1601 generated from upperlayers is fragmented into multiple transport blocks 1602 and 1603. Eachof these transport blocks is sent in a different subframe. For example,transport block 1602 is sent at subframe #m while transport block 1603is sent at subframe #n, where m≠n. The subframe offsets m,n can eitherbe explicitly indicated as part of RRC configuration or can beimplicitly determined based on the triggering of the activation of thedifferent SPS processes for these transport blocks.

Activation

For mode 1 operation, the SPS periodicity can be assigned by the eNodeBbased on several factors, including the geo information transmitted bythe UE. The SPS SL RNTI is pre-configured by the eNodeB duringassociation. The SPS-periodicity and SPS-RNTI for SL can also beconfigured by the eNodeB using RRC using SPS-Config. The existingSPS-Config can be enhanced to additionally include the semi-persistenttransmission configuration for the SL such as semiPersistSched-SL-RNTI(sps-SL-RNTI) and sps-ConfigSL. If SL-SPS is enabled, the PSCCH can bescrambled with the SPS-SL-RNTI for semi-persistent transmissions. Afterthe UE is configured with SPS SL-RNTI, the UE is configured by higherlayers to decode PSCCH with CRC scrambled by the SPS-SL-RNTI.

The UE transmits the PSCCH with CRC scrambled by the SPS-SL-RNTI. Anymessage scrambled by SPS-SL-RNTI is assumed to be a CAM message withsemi-persistent transmissions.

In mode 1 operation, a UE shall monitor PSCCH with CRC scrambled by theSPS-SL-RNTI in every subframe. The set of RBs for semi-persistenttransmission of PSSCH and PSCCH can be configured by the eNB using RRCfor mode 1 operation. Once SPS is configured and enabled by the eNodeB,the SPS information such as the periodicity and number of SPStransmissions for implicit release can be transmitted in the SCI formatin the PSCCH transmissions.

In embodiments of the present disclosure, the activation/release of eachconfiguration is indicated in the DCI format of the (E)PDCCHtransmissions. A few bits in one of the DCI format fields can be re-usedfor this purpose. TABLE 4 shows an example of using a few bits of theDCI format fields for activation of a SPS configuration. If Cconfigurations are supported, at least ceil(log₂(C)) bits are needed foractivation.

TABLE 4 Value Configuration . . . 000 Activate configuration 0 . . . 001Activate configuration 1 . . . 010 Activate configuration 2 . . . . . .

A similar table can be used for release as well.

In embodiments of the present disclosure, simultaneous activation andrelease is supported for fast SPS switching between configurations,where release of one configuration activates another configuration.TABLE 5 shows an example of using few bits of the DCI format fields forsimultaneous activation and release of a SPS configuration. If Cconfigurations are supported, at least 2*ceil(log₂(C)) bits are neededfor supporting simultaneous activation and release. If a currentconfiguration is already active or released and is made active/released,there is no change. i.e. to activate a configuration withoutsimultaneous release, simply release an already released (inactive)configuration. If the same configuration is made active and releasesimultaneously, it can be used to signify that the configuration isre-activated.

TABLE 5 Activation Release Configuration . . . 000 . . . 000 Re-activateconfiguration 0 . . . 000 . . . 001 Activate configuration 0, Releaseconfiguration 1 . . . 000 . . . 010 Activate configuration 0, Releaseconfiguration 2 . . . . . . . . . 001 . . . 000 Activate configuration1, release configuration 0 . . . 001 . . . 001 Re-activate configuration1 . . . 001 . . . 010 Activate configuration 1 & release configuration 2. . . 001 . . . 011 Activate configuration 1 & release configuration 3 .. . . . . . . .

In one example, the fields of the DCI format 5 used for sidelink arereconfigured to support SPS activation and release for V2V, as shown inTABLE 6, assuming the maximum number of SPS configurations for the UE islimited to 4 (2 bits).

TABLE 6 Parameter Bits Usage Resource for PSCCH 6 N/A or set to ‘0’ TPCcommand 1 N/A or set to ‘0’ Resource block assignment and 5-13 All bitsare set to ‘0’ to hopping resource allocation indicate SPSactivation/release Frequency hopping flag 1 N/A or set to ‘0’ TimeResource Pattern (T-RPT) 7 Bits 6-4 is N/A or set to ‘0’ Bits 3-2 isused for release Bits 1-0 is used for activation

The initial resource selection can be provided by the eNodeB. The eNodeBassigns the SPS periodicity and resources for transmission of messages.

Resource Reselection

Resource reselection can be triggered based on the following conditions.

(a) The transmitting UE scans the resource pool every period P, unlessit happens to be transmitting in that period. If there is a significantchange in the resource pool (e.g., above a threshold), or the UEobserves a potential conflict for its next transmission period, the UEreports the conflict to the eNodeB, which can then perform resourcereselection.

(b) In mode 1 operation, the transmitting UE can report the status ofthe shared resource pool to the eNB based on a request from the eNB andthe eNB may take several actions to assist resource allocation. Forexample, the eNB may stop the current SPS transmissions, reconfigurepool resources or request the UE to select a different set of RBs forfuture transmissions within the pool.

SPS Termination

SPS may be terminated by the eNodeB at any time. In addition, the SPSmay be terminated by the eNB based on the following feedbacks (i)-(iii)from the UE.

(i) The UE indicates to the eNB that it does not intend to transmit databefore a transmission associated to an SPS configuration. This could beindicated, for example, on the PUCCH.

(ii) The UE indicates to the eNB of a change in traffic periodicityand/or priority and/or change in geo-location zone in the PUSCH.

(iii) If the UE has no data to transmit, then the UE skips SPStransmission and increases an internal counter. If the number of counteris equal to the pre-determined threshold, then the UE releases the SPSand notifies the release to the eNB.

For mode 1, eNB can activate/re-activate/release SL SPS at any time forthe UE transmissions.

Mode 2 Operation

FIG. 17 shows an example of semi-persistent transmissions from multipleUEs in the shared resource pool for SL according to one embodiment ofthis disclosure.

UE 1701 transmits its CAM messages in 2 symbols within a sub-frame (forexample, if using FDM) or 2 sub-frames within a frame (for example, ifusing TDM). UE 1702 transmits its CAM messages such that in at least 1time instance it can hear the transmissions from UE 1701. If thetransmitting UE 1701 or 1702 does not have any CAM message to transmitat its next intended transmission time, it performs sensing on the setof potential resources it was intending to transmit on. This can allowthe transmitting UE to make a better resource selection choice forfuture transmissions.

Activation

For mode 2 operation, the SPS periodicity can be implicitly assumed to afixed value (for example, 100 ms). The SPS SL RNTI is pre-configured bythe eNodeB during association. The UE transmits the PSCCH with CRCscrambled by the SPS-SL-RNTI. Any message scrambled by SPS-SL-RNTI isassumed to be a CAM message with semi-persistent transmissions.

The transmitting UE first scans the shared pool for K (>=10) periods (ofperiodicity P>=100 ms) to capture at least one CAM transmission from allneighboring UEs. Based on the scan results, the transmitting UE findsthe occupancy pattern of the neighboring UEs and their SPS periodicity.The transmitting UE then selects SPS transmission resources according tothe following criteria: (a) If at least 1 resource is available for allK periods in the scan, that is given first priority for transmission;(b) If at least 1 resource is available for L periods, where 1≤L<K, theUE selects a resource and SPS schedule that minimizes the collision withits periodicity; and (c) If no resource is available, the UE does nottransmit and restarts resource selection.

Resource Reselection

Resource reselection can be triggered based on the following conditions(a) to (c): (a) The transmitting UE scans the resource pool every periodP, unless it happens to be transmitting in that period. If there is asignificant change in the resource pool (e.g., above a threshold) or theUE observes a potential conflict for its next transmission period, theUE performs resource reselection; (b) As increased resource utilizationis observed (e.g. above a threshold), the transmitting UE can lower itsSPS periodicity to accommodate more UEs and perform resourcereselection; and (c) If there is a change required in the periodicity ofthe CAM message transmission of the transmitting UE due to change in UEspeed/direction etc., the UE performs resource reselection.

SPS Termination

SPS may be terminated based on the following conditions: (a) Theresource pool scan shows all resources are occupied; and (b) There is anemergency event for the transmitting UE.

In one embodiment of the present disclosure, when the CAM messageperiodicity changes due to change in vehicle speed, it cancels itscurrent SPS reservation and performs resource reselection. In this case,it temporarily uses separate resources without SPS during the periodwhere the speed is changing. After the speed is stabilized, it performsresource selection again and goes back to a periodic SPS transmission.

FIG. 18 shows an embodiment of the disclosure where the UE stops the SPStransmissions and changes to regular transmissions until the periodicityis stabilized (based on observing the past few transmissions at regularperiodicity). Once the periodicity has stabilized, the UE continuestransmission with the new periodicity. The embodiments shown in FIG. 18are for illustration only. Other embodiments could be used withoutdeparting from the scope of the present disclosure.

FIG. 19 shows an example procedure for transmitting messages usingperiodic and regular resource allocation, according to embodiments ofthe present disclosure. The embodiments shown in FIG. 19 are forillustration only. Other embodiments could be used without departingfrom the scope of the present disclosure.

The UE first starts with a regular allocation in step 1905 and monitorsits traffic generation pattern from the upper layers over a given timeinterval, say 1-10 seconds, for example in step 1910. If the trafficpattern is observed to be periodic with periodicity P within the giventime interval, the UE assigns a periodic resource of periodicity P instep 1915 and transmit messages using periodic resource allocation withperiodicity P in step 1920. As soon as there is a change in periodicity,the UE stops its periodic allocation and returns to a regular allocationin step 1925.

FIG. 20 shows another example procedure for transmitting messages usingperiodic and regular resource allocation, according to embodiments ofthe present disclosure. The embodiments shown in FIG. 20 are forillustration only. Other embodiments could be used without departingfrom the scope of the present disclosure.

The UE first starts with a regular allocation in step 2005 and monitorsits traffic generation pattern from the upper layers over a given timeinterval, say 1-10 seconds, for example in step 2010. To account fordynamic periodic variations, the periodicity is not determined preciselyto P but from a set of periodicities {P₁, P₂, . . . , P_(K)} in step2015, where K is the maximum number of periodicities in the set. In oneexample, K=3 and the periodicities could be {P₁, 2*P_(1,) P₁/2}. In thiscase, each transmission in the SPS could be the current periodicity orthe next one (in both directions) in step 2020.

As soon as there is periodicity observed outside this set, the UE stopsits periodic allocation and returns to a regular allocation instep 2025.The other UEs monitoring the resource pool may detect the periodictransmission of the UE for the purpose of resource selection/avoidanceand in one alternative may only consider the currently transmittedperiodicity in a period as occupied in upcoming periods.

In a second alternative, the monitoring UEs may additionally considerthe resource allocation corresponding to other periodicities in the setas unavailable in upcoming periods. The set of periodicities may beimplicitly indicated, for example by lookup table, preconfiguration, orfixed offset between periods (e.g. 2× or 0.5×, or +/−X ms or slots) ormay be explicitly indicated by physical or higher layer signaling (e.g.in a SA or other dedicated SPS/resource allocation message).

Semi-Persistent Transmissions on the Uplink to the eNB

SPS configuration, activation and release procedures for UL can followexisting SPS procedures in Rel-13.

Distinguishing Message Types by Scrambling

In embodiments of the present disclosure, all periodic messages such asperiodic CAM messages for V2V SL are scrambled by SPS-SL-RNTI whilenon-periodic messages such as DENM messages are scrambled by SL-RNTI.DENM messages, being aperiodic, do not use semi-persistenttransmissions. However, DENM messages can have increased number ofrepetitions within frame or sub-frame to provide higher reliability.

In another embodiment of the invention, only periodic (CAM) messages usea shared resource pool while DENM messages use a dedicated resourcepool. For example, the commTxPoolExceptional field in SIB18 can bere-used for DENM messages for V2V.

In another embodiment of the present disclosure, for V2I transmissionsof aperiodic DENM messages, the DENM messages are transmitted usingregular PUSCH transmissions and are scrambled by C-RNTI.

Performance Validation

FIG. 21 illustrates an example of comparing the different SPS allocationschemes according to embodiments of the present disclosure. Theembodiments shown in FIG. 21 are for illustration only. Otherembodiments could be used without departing from the scope of thepresent disclosure.

In this example, we assume up to 32 exclusive resources are availablefor SPS transmissions. The UEs are assumed to be transmitting 3-5messages per second for speeds between 40-75 km/hr on a freeway. As canbe observed, when the number of UEs in the resource set is less than 32,exclusive allocation works fine with no collisions. However, periodicitybased allocation allows ˜90 UEs to be allocated due to the ability tomultiplex SPS resources in the pool. Random allocation is worse whennumber of UEs<32 but is better than exclusive allocation when number ofUEs get large.

FIG. 22 shows another example of comparing the different SPS allocationschemes according to embodiments of the present disclosure. Theembodiments shown in FIG. 22 are for illustration only. Otherembodiments could be used without departing from the scope of thepresent disclosure.

This example shows an extreme case when all UEs are transmitting 10messages per second. In this case, there is no performance benefit ofperiodicity based allocation since there are no UEs available tomultiplex as all UEs are transmitting at 100 ms periodicity.

FIG. 23 shows yet another example of comparing the different SPSallocation schemes according to embodiments of the present disclosure.In this example, if the UEs are transmitting only 1 message/sec (forexample, at stop sign), the periodicity based allocation showssignificant gains and no collisions are observed.

Since low latency is a critical feature for V2V communication, thecurrent D2D structure where the PSCCH and PSSCH are scheduled acrossmultiple sub-frames in separate resource pools and are time-multiplexedcannot meet the requirements for V2V communication. In the presentdisclosure, we provide resource pool designs for fast resourceallocation, support for semi-persistent scheduling for periodic trafficand support for scheduling emergency DENM event-triggered traffic.

Resource Pool Design

FIG. 24 illustrates an example resource pool structure using FrequencyDivision Multiplexing of SA (PSCCH) and Data (PSSCH) according toillustrative embodiments of the present disclosure. The embodimentsshown in FIG. 24 are for illustration only. Other embodiments could beused without departing from the scope of the present disclosure.

The resource pool for V2V communication is defined as follows: (a) infrequency: by parameters, PRBnum that defines the frequency range inPhysical Resource Block (PRB) bandwidth units; PRBstart and PRBend,which define the location in the frequency domain within the uplinkband; SA-PRBnum that defines the frequency range in Physical ResourceBlock (PRB) bandwidth units that is assigned for SA (PSCCH) transmissionand reception. SA-PRBnum is less than or equal to PRBnum. The SAfrequency bands are defined starting from PRBstart or PRBend, dependingon which of the two bands are in use in the current slot. (b) in thetime domain: by a bitmap that indicates the 1 msec sub-frames used forPSCCH and PSSCH transmissions

FIG. 25 illustrates example resource pool structures using frequencydivision multiplexing of SA and data on separate physical channelsaccording to illustrative embodiments of the present disclosure. Theembodiments shown in FIG. 25 are for illustration only. Otherembodiments could be used without departing from the scope of thepresent disclosure.

The SA and data resources are orthogonal in frequency i.e. separatewithout any overlap. This helps the receiver to look for SA in aparticular set of frequency locations without having to search throughthe entire band. The resources used for each SA transmission is fixed infrequency. The resource location for SA transmission of each UE within aresource pool is indicated by the eNodeB in the DCI format for mode 1transmission.

In some embodiments, the SA transmission may be repeated multiple timeswithin the resource pool to provide improved reliability and to supporthalf-duplex transmissions. At least in the UE autonomous resourceselection mode (mode 2), PSCCH shall be transmitted for every PSSCHtransmission. In case of re-transmissions also, PSCCH should be repeatedin the autonomous mode since it is possible that the receiving UE mayhave missed the PSCCH transmission due to half-duplex issue. Repetitionsof PSSCH and PSCCH, if any, are scheduled within a fixed transmissionperiod.

In case of repetitions in mode 1, when soft combining is required toincrease reliability, the repetition information can be implicitlyobtained from the location of the first transmission indicated by theeNodeB using a mapping rule. The number of repetitions orre-transmissions can be configured by the eNB or can be pre-determined.Also, in cases, where eNB support is not available, PSBCH transmissionscan be used to configure the number of re-transmissions, for example, byusing a bit in the Master Information Block for Sidelink (MIB-SL).

For example, the number of repetitions may be increased to improvereliability under high speed conditions or based on geo-location. Thenumber of repetitions can also be increased to provide higherreliability to support high priority traffic such as emergency messages.

In embodiments of the present disclosure, high Doppler is supported byincreasing the number of repetitions for PSSCH and/or PSCCH. In oneexample, configuration of repetitions is switched between 2 repetitionsand 4 repetitions, which is decided by the eNB and configured via RRCsignaling and/or configuring a bit in the PSBCH transmissions to providethis distinction.

The SA contains explicit information about the frequency location ofdata transmission(s) to provide increased flexibility for schedulingresources. This is required since the message can be of variable sizeand may use variable modulation and coding rates, which makes the amountof resources used in frequency variable. The data can be composed ofmultiple duplicate transport blocks for increased reliability. Thus,PSSCH and PSCCH are transmitted simultaneously with separate DFTprecoding within the same sub-frame and are not contiguous in frequency.

Each PSCCH and PSSCH should be transmitted at least twice to solve thehalf-duplex issue. In this case, it is important that multiple UEs donot select the same offset for repetition(s) with respect to their firsttransmission. One method to solve this issue would be to require thatthe transmission of the repetition(s) of PSSCH and PSCCH be in a randomtime offset with respect to their first transmissions. If a PSSCHtransmission is sent over multiple sub-frames, the transmission time ofthose sub-frames are also randomized.

In embodiments of the present disclosure, multiple resource allocationmodes are supported for PSSCH transmission: (a) Distributed resourcegroup allocation: i. This mode is similar to Type-0 mode used for DLresource allocation; and ii. This mode can be used for autonomous mode 2operation, for example, to reduce sensing and resource allocationrequirements. It can also help provide frequency diversity and increasedtransmission power.

(b) Continuous allocation: i. This mode is similar to Type-2 mode usedfor DL resource allocation and ii. This mode can be used for mode-1operation, for example, and can give lower MPR

(c) Interlaced allocation: i. This mode is based on the interlacingbased resource allocation used for UL LAA; ii. This mode can be used tosupport co-existence with DSRC in certain geographical locations and/orin certain shared frequency bands; iii. The PSCCH is always transmittedin the same subframe as PSSCH in the interlaced allocation mode. Theentire carrier bandwidth is used for transmission in this mode. ThePSCCH also follows the interlace pattern of the PSSCH, if applicable;and iv. This method can provide frequency diversity for transmission andalso benefit sensing in Mode 2 where a signal can be observed withperiodicity across the resource.

The allocation mode can be configured by the eNB. All UEs in a givenresource pool shall use the same allocation mode.

FIGS. 26A to 26C illustrate the resource allocations for PSSCHtransmissions according to embodiments of the present disclosure. Theembodiments shown in FIGS. 26A to 26C are for illustration only. Otherembodiments could be used without departing from the scope of thepresent disclosure.

FIG. 26A shows a distributed resource allocation mode, where resourcesare allocated in groups of RBs of size P. A bit map is used to indicatethe groups that are used, requiring a total of ceil(N/P) bits in thePSCCH for indicating the resources used for transmission. The RBG size Pcan be fixed and can be a function of the sidelink transmissionbandwidth. If the amount of data to be transmitted requires less than Presources, rate matching is performed to utilize the entire RB groupsize P.

FIG. 26B shows a contiguous resource allocation mode, where theresources are signaled in terms of a starting position S and number ofRBs used K. PRB allocations in this mode can vary from a single PRB to amaximum number, spanning the entire SL bandwidth. This requires anindication using ceil(log₂(N(N+1))) bits in the PSCCH.

FIG. 26C shows an interlaced resource allocation mode where theresources are interlaced across the bandwidth. The resources areindicated by a starting position (S) and the interlace offset (M).Multiple interlaces can also be supported with different startingpositions.

DSRC Co-Existence Support

A. V2V Transmission Behaviour for Co-Existence with DSRC

There can be multiple approaches to enable detection of V2Vtransmissions by DSRC.

Option 1: Transmission of a Periodic Preamble that can be Detected byDSRC Receivers

FIG. 27 illustrates an example periodic preamble that can be transmittedby V2V in order to facilitate detection by DSRC receivers according toembodiments of the present disclosure. 26A to 26C

While different UEs may use different resources for PSCCH and PS SCH,they use the same resource for the preamble. The preamble is SFNaccumulated, assuming all UEs transmit the same preamble.

Option 2: Wideband Transmissions Enabling CS/CCA at DSRC Receivers

FIG. 28 shows an option using wideband transmissions to enable carriersense/clear channel assessment (CS/CCA) at DSRC receivers according toembodiments of the present disclosure.

In this scheme, a multi-cluster transmission with a fixed interlacepattern is used for PSSCH and PSCCH transmissions. This allows thetransmitter to meet bandwidth occupancy requirements (and highertransmit power in certain regulations) and supports multiplexing of UEsin the bandwidth with frequency diversity across the band. In this case,DSRC receivers may not be able to distinguish LTE V2V vs. another DSRCtransmission purely based on CS/CCA but may be able to differentiatebased on DSRC preamble detection.

In embodiments of the present disclosure, the RBs assigned for PSCCHtransmissions follow the same interlace pattern as the PSSCH. If thenumber of RBs allocated for PSCCH exceed the interlace offset M, thePSCCH is repeated in sub-frame to follow the interlace pattern as shownin FIG. 28. It is allowed to perform rate matching in the interlace incase of insufficient data size.

B. V2V Reception Behaviour to Co-Exist with DSRC

Listen-before-talk (LBT) based approaches can be used for V2V receptionbehaviour to co-exist with DSRC. V2V devices can first perform an energyscan over the entire shared channel bandwidth before transmitting. ACS/CCA procedure with parameters defined to meet regulatory constraintsfor shared channel operation to support co-existence can be adopted.DSRC signals can be differentiated with LTE V2V signals based on SA andenergy sensing features agreed for LTE V2V. When a DSRC signal isdetected, V2V devices may stop V2V transmissions and report thedetection of a DSRC transmission to the eNB at the earliest availableopportunity. The eNB may then take the necessary action, such asevaluating a different channel for V2V transmissions. It is alsopossible for the eNB to perform the sensing as well.

FIG. 29 shows how a V2V receiver can distinguish between a DSRCtransmission and a LTE V2V transmission, according to the embodiments ofthis disclosure. A DSRC transmission is full bandwidth and cannot bedecoded by the V2V receiver. In this case, the LTE receiver assumes thatthis is a DSRC transmission and takes the necessary action. On the otherhand, a V2V transmission is interlaced in frequency and the control (SA)can be detected by the V2V receiver to identify it is a LTE V2Vtransmission and hence, no action needs to be taken regardingco-existence.

PSCCH Contents

The PSCCH contents are as shown in below TABLE 7.

TABLE 7 Parameter Usage Resource for Provides the information of thetransmitting UE of the resource to be used PSCCH for SCI format 0transmissions within the PSCCH pool. Transmit power The transmit powerused for transmission of PSSCH Resource block give to the receivingdevices the information of the resources of the PSSCH assignment thatthey shall decode in the frequency domain Time offset Indicates the timeoffset between the PSSCH and PSCCH based on an indication allowedconfiguration range Number of Indicates number of repetitions used forPSSCH repetitions UE ID The ID of the transmitting device

To aid the Patent Office and any readers of any patent issued on thisapplication in interpreting the claims appended hereto, applicants wishto note that they do not intend any of the appended claims or claimelements to invoke 35 U.S.C. § 112(f) unless the words “means for” or“step for” are explicitly used in the particular claim. Use of any otherterm, including without limitation “mechanism,” “module,” “device,”“unit,” “component,” “element,” “member,” “apparatus,” “machine,”“system,” “processor,” or “controller,” within a claim is understood bythe applicants to refer to structures known to those skilled in therelevant art and is not intended to invoke 35 U.S.C. § 112(f).

Although the present disclosure has been described with an exampleembodiment, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

What is claimed:
 1. A user equipment (UE) in a wireless communicationnetwork, the UE comprising: a receiver configured to receive at leastone semi-persistent scheduling (SPS) configuration among a plurality ofSPS configurations from a base station, wherein each of the plurality ofSPS configurations configures the UE with a periodicity of a sidelinktransmission to be transmitted to another UE, and wherein an activationor a release of each SPS configuration is indicated in a DownlinkControl Information (DCI) format of a Physical Downlink Control Channel(PDCCH) transmission; and a transmitter configured to: transmit thesidelink transmission with a periodicity according to the at least onereceived SPS configuration; and transmit a scheduling assignment (SA)that indicates a sidelink data resource, and wherein a resource for theSA and the sidelink data resource are orthogonal to each other infrequency-time domain.
 2. The UE of claim 1, wherein, when a traffictype changes, a corresponding SPS configuration is activated and anon-corresponding SPS is released.
 3. The UE of claim 1, wherein, when achange is required in the periodicity of the sidelink transmission, theUE is configured to perform a resource reselection.
 4. The UE of claim1, wherein: the SA includes a Physical Sidelink Control Channel (PSCCH),the sidelink data resource includes a Physical Sidelink Shared Channel(PSSCH), a PSCCH is transmitted for every PSSCH transmission, and aresource location for SA transmission of each UE within a resource poolis indicated by the base station in a DCI format.
 5. The UE of claim 4,wherein a transmission of the PSSCH and the PSCCH is repeated in arandom time offset with respect to a first transmission or in a fixedtransmission period.
 6. A base station (BS) in a wireless communicationnetwork, the base station comprising: a controller configured to selectat least one semi-persistent scheduling (SPS) configuration among aplurality of SPS configurations for a user equipment (UE), wherein eachof the plurality of SPS configurations configures the UE with aperiodicity of a sidelink transmission to be transmitted to another UE,and wherein an activation or a release of each SPS configuration isindicated in a Downlink Control Information (DCI) format of a PhysicalDownlink Control Channel (PDCCH) transmission; and a transmitterconfigured to transmit the selected at least one SPS configuration tothe UE and to transmit information on a resource for a schedulingassignment (SA) that indicates a sidelink data resource, wherein theresource for SA and the sidelink data resource are orthogonal to eachother in frequency-time domain.
 7. The BS of claim 6, wherein, when atraffic type changes, a corresponding SPS configuration is activated,and a non-corresponding SPS is released.
 8. The BS of claim 6, wherein,when a change is required in a periodicity of the sidelink transmission,the UE performs a resource reselection.
 9. The BS of claim 6, wherein:the SA includes a Physical Sidelink Control Channel (PSCCH), thesidelink data resource includes a Physical Sidelink Shared Channel(PSSCH), a PSCCH is transmitted for every PSSCH transmission, and aresource location for SA transmission of each UE within a resource poolis indicated by the base station in a DCI format.
 10. The BS of claim 9,wherein a transmission of the PSSCH and the PSCCH is repeated in arandom time offset with respect to a first transmission or in a fixedtransmission period.
 11. A method for operating a user equipment (UE) ina wireless communication network, the method comprising: receiving atleast one semi-persistent scheduling (SPS) configuration among aplurality of SPS configurations from a base station, wherein each of theplurality of SPS configurations configures the UE with a periodicity ofa sidelink transmission to be transmitted to another UE, and wherein anactivation or a release of each SPS configuration is indicated in aDownlink Control Information (DCI) format of a Physical Downlink ControlChannel (PDCCH) transmission; transmitting a scheduling assignment (SA)that indicates a sidelink data resource, wherein a resource for the SAand the sidelink data resource are orthogonal to each other infrequency-time domain; and transmitting the sidelink transmission with aperiodicity according to the at least one received SPS configuration.12. The method of claim 11, wherein, when a traffic type changes, acorresponding SPS configuration is activated and a non-corresponding SPSis released.
 13. The method of claim 11, further comprising, when achange is required in the periodicity of the sidelink transmission,performing a resource reselection.
 14. The method of claim 11, wherein:the SA includes a Physical Sidelink Control Channel (PSCCH), thesidelink data resource includes a Physical Sidelink Shared Channel(PSSCH), a PSCCH is transmitted for every PSSCH transmission, and aresource location for SA transmission of each UE within a resource poolis indicated by the base station in a DCI format.